A couple of very obvious tipoffs should make it apparent to regular Google visitors that a malicious version of the search engine's home page has been substituted for the real thing.

In the Trend Micro report about malware causing redirections to a fake Google homepage, researchers included a screenshot of that page. A couple of things stand out immediately.

The malicious page tells the victim they need to let an add-on install itself to make Google run properly; helpfully, it offers a click here to download link. No add-on has ever been needed to enable Google's sparse home page to function correctly.